Transcript Cell mediated immunity

ROLE OF MICRONUTRIENTS ON
ANIMAL IMMUNITY
DR.C.KATHIRVELAN, M.V.Sc, PhD
Assistant professor
Department of Animal Nutrition
College of Veterinary Science
S.K.Nagar, Gujarat State 385 506
INDIA
Respiratory burst
Neutrophil
H20
Bacteria
GSHpx
H202
Bacteria
SOD
NADPH OXIDASE
2O2
2O-2
2 e-
NADPH
NADP+
Chew,1996
INTRODUCTION
Nutrition interact with animal immune system
(Pring and Ahmed,1993)
Micronutrients (Minerals and Vitamins)
Minerals Zn, Cu,Cr.Se,Mn, Fe,Co
Vitamins like E,beta carotene and vitamin
A,Vitamin C
 Stress condition
The requirement of micronutrient for optimal
immune response is greater than the amount
required for growth and reproduction
(Harmon,1994; Scaletti,1992)
Micronutrients
Minerals
Zinc
Copper
Chromium
Selenium
Vitamins (Antioxidants)
Vitamin E
Carotenoids (beta carotene ) and Vitamin A
IMMUNITY
Immunity refers to,reactions by an animal body to
foreign substances such as microbes and various
macro molecules ( Abbas et al.,1991)
Immune system
A collection of cells and molecules that protect
the body against infection, malignancy and
damaged cells ( Abbas et al., 1991)
IMMUNITY
INNATE
•Physical and chemical barriers
•Phagocytes
(Neutrophils & Macrophages)
-Inflammatory process.
ACQUIRED
Specific towards
particular antigen and
enhanced with repeated
exposure
ACQUIRED IMMUNNE
RESPONSE
HUMORAL
•Mediated by
B lymphocytes.
CELL MEDIATED
•Mediated by
T lymphocytes
(Galyean et al.,1999)
B lymphocytes
• Mature
in bone marrow
•Antigen binding receptor in their membrane
B cells
Memory cells
Plasma cells
(Chew,1996)
T lymphocytes
•Mature in thymus gland
•Function to;
Killing infected cells.
Stimulate microbial and cytotoxic activity of immune effecter cells
•T cell membrane receptor.
• Membrane protein Major Histo Compatibility (MHC) molecule.
•Three types of subpopulation
T helper cells (Th cells)
T cyto toxic cells (Tc)
T suppressor cells (Ts)
•T helper cells
Secrete growth factor –cytokines.
Having membrane glycoprotein CD4
(Chew, 1996)
Cells of the immune system
• B cells
• T cells
• NK cells
• Monocytes/macrophages
• Neutrophils
• Eosinophils
• Basophils
(Chew,1996)
Measures of immune response
Humoral immune response
Measured by estimating the antibody (Ig) produced
- Zinc turbidity method (McEwan and Fisher,1970)
Measures of immune response
Cell mediated immune response
•Lymphocyte transformation test , i.e Blastogenesis
In vitro assay measures mitosis of cultured lymphocytes in
response to mitogenic chemicals ( E.g.Concanavalin A ) by
counting radio activity [counts per minute (cpm)] incorporated in
to newly synthesized DNA from radio labelled precursors.This is
expressed as Stimulation Index (SI) (Larson,1979)
Mean cpm in culture with mitogen
Mean cpm in culture without mitogen
• In in vivo, antigen instead of Con A
Mitogen
• Agents capable of inducing cell division in a high
percentage of T cells or B cells .
• Poly clonal activators.
Characteristics
ConcanavalinA
(Con A)
Phytohemoagglutinin
(PHA)
Pokeweed Mitogen
(PWM)
Source
Jack bean
Kidney bean
Poke weed
Target cells
B cells
T cells
T cells and B cells
Burton,1995
MINERALS
Zinc
Zinc is component of numerous enzymes
Super oxide dismutase (SOD)
RNA Polymerase
DNA polymerase
Ribonulease
Thymidine kinase
Zinc..
Zinc influences host defence mechanisam via:
•
Phagocytic activity
•
Cell mediated immunity
•
Humoral immunity
Phagocytic activity
Zinc enhances phagocytic activity of macrophages
and neutrophils (Babior, 1978)
Phagocytic activity through respiratory burst
( McCord & Fridovich,1969 ; Chew, 1996)
Increase release of vasoactive amines by basophils
Zinc..
Cell mediated immunity;
Enhances T cell mediated immunity
Zinc is a cofactor for thymic hormone thymulin
Thymulin deficiency
Impaired T lymphocyte
proliferation
Impaired T lymphocyte function
Humoral immunity:
Increases antibody production
(Bach,1983)
Copper..
Copper immune mechanism
Phagocytic activity
Neutrophils
Monocyte
Humoral Response:
•Increases antibody production
•Ab production decreased in Cu deficient diet
(Gengelbech and spears, 1998)
COPPER
Copper is component of
•Superoxide dismutase (SOD)
•Ceruloplasmin.
•Modulate inflammatory response by phagocytosis
Copper..
Cell mediated immunity
•Mainly through T-lymphocytes (Th,Tc) by
cytokine production
• inhibit viral replication
•Interlukin production
B cell maturation
NK cell activity
Chemo tactic attraction
Tumour necrosis factor 
•Act on tumor cell-kill it.
CHROMIUM
Component of Glucose Tolerance Factor (GTF).
* Potenciate the insulin activity (Cheng and Mowat,1999)
* Facilitate interaction between insulin and insulin receptor in
target tissue.
* Reduces cortisol level in stress.
Cont..
In stress
Increased cortisol
in blood
Antagonist the
insulin action
Prevents glucose uptake
by insulin receptor
Prevent entry of glucose
to vital tissue
Immune system
under stress.
(Orth,1992)
VITAMINS
Vitamins
•Act as natural antioxidant
•Includes Beta carotene and vitamin A, Vitamin E, Vitamin C
•Protect tissue against damage caused by free radicals.
•Free radicals are,
•
Generated in normal cellular metabolism
•
React with enzymes, DNA and damage the tissue
•
Common free radicals are super oxide, hydrogen
peroxide, hydroxyl radical, fatty acid radical
Antioxidant system of mammalian cells
Component
location
Nutrient
involved
function
Superoxide
dismutase
cytosol
Cu,Zn,Mn
An enzyme that converts super
oxide to hydrogen peroxide
Glutathione
peroxidase
cytosol
Se
An enzyme that converts
hydrogen peroxide to water
Catalase
cytosol
Fe
An enzyme that converts
Hydrogen peroxide to water
Alpha tocopherol
membrane Vitamin E
Break fatty acid peroxidation
chain reaction
Carotene
membrane Carotene
Prevents initiation of fatty acid
peroxidation chain reactions
Smith et al.,1984
Role of antioxidant on immunity
Miller and
Slebodzinska, 1993
Vitamin E and Selenium
Vitamin E
• Vit E reduces harmful lipid free radicals.
• Enhances phagocytic activity of neutrophils,
macrophages and NK cells. (Miller,1993)
• It is major antioxidant in the blood.
Selenium
•Biochemical role through glutathione peroxide
•Enhance neutrophil function
Cont…
Vitamin E and Selenium
• Both vitamin E and Se influences the function
of immune cells especially in mammary gland
immunity
•Cows are immuno suppressed when plasma
concentration of vitamin E and Se is low
(Grasso et al., 1990)
Milk and plasma levels of vitamin E in healthy and
mastitis cows
Milk
Plasma
0.6
5
0.5
4
mg/L
mg/L
0.4
0.3
3
2
1
0.2
0
0.1
Healthy
Mastitis
0
Healthy
n=75
n=75
Mastitis
Aroshi etal, 1986
•Supplementation of Vit E (1500 IU) and Se (0.3ppm) increases plasma
concentration of vitamin E and reduce incidence of mastitis (Smith,1986)
Plasma concentration alpha tocoferol
•Feeding heifers with supplemented vitamin E (1500 IU/d) and giving a
selenium inj (0.3 ppm) 21 days post calving reduced several measures of
mastitis.(Smith etal, 1984)
IMI duration
IMI at calving
Clinical
Mastitis
High SCC
cow s
0
20
40
% reduction
60
80
Beta carotene
•Act as an antioxidant
Beta carotene:
•Enhances phagocytic activity of neutrophils- myloperoxidase
enzyme
•Enhances phagocytic activity of macrophages – peroxidase.
•Increases lymphocyte toxicity
CONCLUSION
•Zinc and copper enhances cell & humoral mediated immunity
•Chromium stimulate immune response in stress conditions
•Vitamin E and Se stimulate immunity against intra mammary
infection
•Beta carotene enhances both cell mediated and humoral
response